In recent years, by installing a relay station in a vehicle such as a railway train or a bus, services that allow a passenger to perform wireless communication with the relay station using a wireless terminal and use a mobile wireless communication system such as a mobile worldwide interoperability for microwave access (WiMAX) have been provided.
Generally, in the mobile wireless communication system, the wireless terminal calculates a long-term average value of receiving power of a radio signal from each base station and the relay station at a regular time interval, selects one having a largest long-term average value as a connection destination base station, and is wirelessly connected to the selected base station or relay station.
In order to prevent the wireless terminal inside the vehicle from unnecessarily performing the hand-off process, the wireless terminal is preferably continuously connected to the relay station inside the vehicle. However, when the vehicle is moving, the radio signal from the base station outside the vehicle enters the vehicle through a window, and the wireless terminal may receive the radio signal with the good quality (power). In this case, the wireless terminal attempts to connect with the base station outside the vehicle other than the relay station inside the vehicle.
That is, as the vehicle moves, the wireless terminal is connected with the base station outside the vehicle that temporarily has the good quality or the relay station inside the vehicle. Thus, the hand-off (switching) process in which the wireless terminal performs with a connection destination base station may unnecessarily increase. Since the wireless terminal cannot perform data communication during the hand-off process, if the hand-off process increases, there is a problem in that communication efficiency deteriorates. Further, if the hand-off process increases, there is also a problem in that power consumption of the wireless terminal increases.